Foam-based interfacing structure method and apparatus

ABSTRACT

A cushioning component for use with a mask is constructed of foam material. A patient contacting surface, that is adapted to contact a patient, in use, has a rounded cross sectional profile and a base surface opposed to the patient contacting surface.

CROSS-REFERENCE TO APPLICATION

This application claims the benefit of Australian Provisional PatentApplication Nos. AU 2008904769, filed Sep. 12, 2008, and AU 2008904778,filed Sep. 15, 2008, each of which is incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

The present invention relates to an interface between a human and apiece of equipment, for example respiratory devices that include afoam-based interfacing structure,

BACKGROUND OF THE INVENTION

In a number of fields, such as respiratory therapy, apparatus fordelivery of therapy includes a rigid component and a soft, cushioningcomponent positioned between a patient and the rigid component.

In the case of a respiratory device, the rigid component may be a maskframe defining a nose and/or mouth-receiving chamber. The mask frame mayinclude a flange around its periphery or other connecting means. Thecushioning component may be glued or otherwise coupled to the flange orconnecting means.

The cushioning component may form aa seal with the skin of the patientin some forms of respiratory therapy. In other devices, for exampleheadphones, it may not be necessary for aa seal to be formed.

SUMMARY OF THE INVENTION

A first aspect of the invention is to provide a mask assembly with afoam interfacing structure.

Another aspect of the invention is to provide a mask assembly with afoam interfacing structure where at least a part of the foam (e.g., anunskinned part of the foam) is in direct contact with the skin of themask user.

Another aspect of the invention is to provide a mask assembly with afoam interfacing structure where the foam is unskinned and has acellular structure of the foam in direct contact with the skin of themask user.

Another aspect of the invention is to provide a mask assembly with aremovable foam interfacing structure.

Another aspect of the invention is to provide a mask assembly with atleast two different types of removably replaceable interfacingstructures.

Another aspect of the invention is to include a softer interfacingstructure having portion adapted for engagement with a more rigidcomponent.

Another aspect of the invention is to provide a respiratory maskassembly including a frame and an interfacing structure wherein theinterfacing structure includes a foam-based cushion component and a clipportion adapted for removable engagement with the frame portion.

Another aspect of the invention is to provide a support structure for acushioning component wherein the support structure supports thecushioning element on one side and allows movement on another side.

Another aspect of the invention relates to a cushion for a respiratorymask including a clip portion and a cushioning component wherein thecushioning component is constructed from a foam material and the clipportion is narrower than the cushioning component.

Another aspect of the invention relates to a respiratory mask assemblyincluding a frame having a channel and an interfacing structureincluding a clip portion adapted for interference seal and retention inthe channel. The interfacing structure includes a cushion componentconstructed from foam and having a wider width than the clip portion.

Another aspect is a foam-based cushioning component preferably having afirst cross-section in a nasal bridge region, a second cross-section ina lip region and a third cross-section in the cheek region.

Another aspect is a method of manufacturing a cushioning component,e.g., die cutting and/or machining, etc.

Another aspect is a method of insert molding a clip component to acushioning component to form an interfacing structure.

Another aspect is a cushioning component for use with a mask, whereinthe cushioning component is constructed of foam material. A patientcontacting surface, that is adapted to contact a patient, in use, mayhave a rounded cross sectional profile and a base surface opposed to thepatient contacting surface.

Another aspect is a removable interfacing structure for use with a maskincluding a cushioning component constructed of foam material wherein apatient contacting surface that is adapted to contact a patient, in use,has a rounded cross sectional profile and a base surface opposed to thepatient contacting surface is joined to a clip portion, and wherein theclip portion is adapted to be removably joined to a frame of the mask.

Another aspect is a mask including a removable interfacing structure anda frame, wherein the interfacing structure includes a clip portion and acushioning component constructed of foam material having a patientcontacting surface that is adapted to contact a patient, in use, has arounded cross sectional profile and a base surface opposed to thepatient contacting surface is joined to the clip portion, and whereinthe clip portion is adapted to be removably joined to a frame of themask.

Another aspect is a mask including a frame and an interfacing structure,wherein the interfacing structure includes a clip portion joined tocushioning component, and wherein the frame is more rigid than the clipportion and the clip portion is more rigid than the cushioning portion.

Another aspect is a cushioning component for use with a mask, wherein atleast a portion of the cross section of the cushioning componentincludes an inner side defined by the side facing the centre of themask, an outer side defined by a side facing away from the centre of themask and a base side facing the frame or clip portion, wherein thelength of outer side is greater than the inner side.

Another aspect is an interfacing structure for a mask including a clipportion joined to a cushioning component, wherein an upper surface ofthe clip portion is joined to a base surface of the cushioning componentand wherein at least a portion of the upper surface is angled to providea moment force on cushioning component, when force is applied into thecushioning component.

Another aspect is an interfacing structure for a mask including a clipportion joined to a cushioning component, wherein an upper surface ofthe clip portion is joined to a base surface of the cushioning componentand wherein the cross sectional width of the clip portion is less thanthe cross sectional width of the cushioning component.

Another aspect is a cushioning component for use with a mask, wherein atleast a portion of the cross section of the cushioning componentincludes an inner side defined by the side facing the centre of themask, an outer side defined by a side facing away from the centre of themask and a base side facing the frame or clip portion, wherein the outerside further includes at least an upper and a lower portion, wherein theupper portion is positioned at a reduced angle in comparison to thelower portion.

Another aspect is a nasal mask including a frame removably connected toan interfacing structure, wherein the interfacing structure includes acushioning component constructed of foam material, and wherein theheight of the interfacing structure is reduced in relation to regionthat is adapted to contact the upper lip region of a patient's face,

One aspect of the present technology relates to a respiratory maskincluding a frame, a foam cushion and a substructure. The mask includesa nose receiving cavity. The cushion includes at least two sides: aninner side wall, which may be a wall at least partially facing thecavity; and an outer side wall. The foam cushion is soft and conforming.The substructure is constructed from a more rigid material. The foamcushion is adapted to form a seal with at least one region of a face ofa patient. In use the foam cushion is supported by the substructure. Aconnecting surface of the substructure is defined. A patient side of thefoam cushion is defined. A non-patient side of the cushion is defined.In use the non-patient side of the cushion is arranged adjacent theconnecting surface of the substructure. In one form the foam cushion isglued to the substructure. In another form the foam cushion is insertmoulded with the substructure. A first region of the face is defined asa corner of the mouth of the patient. A second region of the face isdefined as a chin region, or alternatively a lip region of the face ofthe patient. An interior region of the cushion is defined as the regionor cavity into which a nose of a patient is inserted in use.

In one form, a part of the connecting surface in use adjacent the firstregion is structured in to direct a corresponding portion of the foamcushion in an inward direction towards the interior region of thecushion in the first region in use. The cross-section of the cushiondefines a radial axis and a longitudinal axis is normal to said radialaxis. Preferably, at least a portion of the foam cushion is adapted torotate towards the centre of the mask about said longitudinal axis whenpressure is applied into the cushion by the patient's face and whereinat least a portion of the outer side wall of said cushion is adapted toform a seal against the face of a patient.

Wherein portions of the cushion rotate or roll inwards towards thecentre of the mask. The feature of rolling or rotating inwards mayprevent or limits the possibility of the seal “blowing out” when airpressure is applied to the mask cavity, “Blowing out” is defined by theseal between the cushion and the patient's face breaking due to pressureexerted by air pressure lifting the cushion from a sealing relationshipwith the face.

In one form, a part of the connecting surface in use adjacent the secondregion is structured to direct the foam in an outward direction awayfrom the interior region of the cushion in the second region in use. Thecross-section of the cushion defines a radial axis and a longitudinalaxis is normal to said radial axis. Preferably, at least a portion ofthe foam cushion is adapted to rotate away from the centre of the maskabout said longitudinal axis when pressure is applied into the cushionby the patient's face and wherein at least a portion of the outer sidewall of said cushion is adapted to form a seal against the face of apatient.

Preferably, further portions of the cushion may rotate inwards oroutwards relative to the centre of the mask in positions defined asbeing proximal to the patient's chin. In regions or portions of thecushion that can rotate or roll inwards and outwards, this rotation mayallow for seal to accommodate different sizes of chin and/or accommodatemoderate amounts of mouth or jaw movement that may otherwise destructthe seal formed between the mask and the patient's face.

Another aspect of the present technology is a foam cushion for arespiratory mask wherein the cushion includes a face-contacting portionarranged in use to be adjacent the face of the patient.

Preferably in at least some regions of the face contacting portion, across section of the cushion tapers from a wider cross-section to anarrower cross-section closer to the face. The tapered portion definesan inside surface adjacent an interior of the cushion and an outsidesurface. The inside surface and the outside surface may be adjacent, inanother form they may be non-adjacent. The inside and outside surfacesmay be arranged at an acute angle with respect to one another. In oneform in cross-section the outside surface is longer than the insidesurface in certain regions of the cushion, preferably in the nasalbridge region, or in the cheek region, or more preferably in both. Inone form the inside and outside surfaces have the same length in a chinregion. In one form in a lip region the inside surface is longer thanthe outside surface in cross-section.

In one form, the cushion is structured to at least partially form a sealon an outside surface of a face in a chin region of the cushion. We havefound that a tapered sealing portion may improve the seal.

Other aspects are directed to methods for manufacturing the foamcushioning elements described above.

Other aspects, features, and advantages of this invention will becomeapparent from the following detailed description when taken inconjunction with the accompanying drawings, which are a part of thisdisclosure and which illustrate, by way of example, principles of thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the variousembodiments of this invention. In such drawings:

FIG. 1 shows a side view of a mask assembly including a foam interfacingstructure according to an embodiment of the invention;

FIG. 2 shows a schematic diagram of a channel of a portion of a maskframe and a clip portion of an interfacing structure retained by aninterference fit according to an embodiment of the invention;

FIGS. 3 a, 3 b, and 3 c show a range of rib engagement fittingarrangements between a mask frame and a clip portion of an interfacingstructure according to embodiments of the invention;

FIG. 4 a shows a patient contacting side of an interfacing structureaccording to an embodiment of the invention;

FIG. 4 b shows a bottom view of the interfacing structure of FIG. 4 a;

FIG. 4 c shows a top view of the interfacing structure of FIG. 4 a;

FIG. 4 d shows a side view of the interfacing structure of FIG. 4 a;

FIG. 4 e shows a frame contacting side of the interfacing structure ofFIG. 4 a;

FIG. 4 f shows a patient contacting side isometric view of theinterfacing structure of FIG. 4 a;

FIG. 4 g shows a frame contacting side isometric view of the interfacingstructure of FIG. 4 a;

FIG. 5 a is a plan view showing a die cut interfacing structure whereinthe clip portion includes a slot for engagement with the frame accordingto an embodiment of the invention;

FIG. 5 b is an isometric view of the interfacing structure shown in FIG.5 a;

FIG. 5 c is an assembly view of the interfacing structure shown in FIG.5 a with a mask frame;

FIG. 6 a shows a cross-section from a prior art nasal mask with foamcushion;

FIG. 6 b shows a detail in the nasal bridge region of the mask of FIG. 6a;

FIG. 7 a shows an elevation view detail from the frame side of theinterfacing structure shown in FIG. 4 e;

FIG. 7 b is a cross-section along line 7 b-7 b of FIG. 7 a;

FIG. 7 c is a cross-sectional view showing the interfacing structure ofFIGS. 7 a and 7 b in use;

FIG. 8 is a cross-sectional view showing the assembly of the interfacingstructure of FIGS. 7 a and 7 b and a frame according to an embodiment ofthe invention;

FIGS. 9 a to 9 d show various views of a foam-based interfacingstructure according to an embodiment of the present invention;

FIGS. 10 a to 10 e show various views of a foam-based interfacingstructure according to another embodiment of the present invention;

FIGS. 11 a to 11 c show various views of a foam-based interfacingstructure according to another embodiment of the present invention;

FIGS. 12 a to 12 f show various views of a foam-based interfacingstructure according to another embodiment of the present invention;

FIG. 13 is a perspective view of a clip portion according to anembodiment of the present invention;

FIGS. 14 a to 14 f show various views of a foam-based interfacingstructure according to an embodiment of the present invention;

FIGS. 15 a to 15 e show various views of a cushion-to-frame component ofthe interfacing structure shown in FIGS. 14 a to 14 f;

FIGS. 16 a to 16 i show various views of the cushioning component of theinterfacing structure shown in FIGS. 14 a to 14 f;

FIGS. 17 a to 17 h illustrate a tool and manufacturing process formanufacturing an interfacing structure according to an embodiment of thepresent invention;

FIGS. 18 a to 18 c show various views of a tool for molding a clipportion according to an embodiment of the present invention;

FIG. 19 is a front view of a further embodiment of a full facecushioning component;

FIGS. 20-25 depict various cross-sectional views of the embodiment shownin FIG. 19;

FIG. 26 is a front view of a further embodiment showing an interfacingstructure for use with a full face mask including a cushioning componentand clip portion;

FIGS. 27-32 depict various cross-sectional views of the embodiment shownin FIG. 26. FIG. 29 defines a horizontal plane of connection between thecushion and the clip portion. In FIGS. 30 to 32 the plane of connectionis at an angle with respect to the horizontal, In FIG. 30 the plane ofconnection is at a downward angle when moving from the outside to theinside of the interfacing portion, in FIG. 32 the plane of connection isat an upward angle when moving from the outside to the inside of theinterfacing portion.

FIG. 33 is a perspective view of full face interfacing structureincluding a cushioning component and clip portion;

FIG. 34 is a side view of the embodiment shown in FIG. 33;

FIG. 35 is a top view of the embodiment shown in FIG. 33;

FIG. 36 is a bottom view of the embodiment shown in FIG. 33;

FIG. 37 is a back view of the embodiment shown in FIG. 33;

FIG. 38 is a front view of the embodiment shown in FIG. 33;

FIG. 39 is a front view of a further embodiment of a interfacingstructure for use with a nasal mask;

FIG. 40 is a top view of the embodiment shown in FIG. 39;

FIG. 41 is a bottom view of the embodiment shown in FIG. 39;

FIG. 42 is a side view of the embodiment shown in FIG. 39;

FIG. 43 is a back view of the embodiment shown in FIG. 39;

FIG. 44 is a front view of a further embodiment of an interfacingstructure for use with a nasal mask;

FIGS. 45-47 depict various cross-sectional views of the embodiment shownin FIG. 44;

FIG. 48 is a chart showing exemplary material properties for a cushioncomponent according to an embodiment of the invention;

FIG. 49 is a chart showing exemplary material properties for a clipportion according to an embodiment of the invention;

FIGS. 50-1 to 57-2 illustrate alternative mechanisms for attaching aclip portion to a frame according to embodiments of the invention;

FIGS. 58 and 59 illustrate the rolling effect of a cushioning componentaccording to an embodiment of the invention;

FIGS. 60-1 to 60-8 illustrate different parameters and apparatus fortesting air permeability according to an embodiment of the invention;

FIG. 61 illustrates apparatus for testing hardness according to anembodiment of the invention;

FIGS. 62-1 to 62-2 illustrate different parameters and apparatus fortesting tensile strength according to an embodiment of the invention;

FIGS. 63-1 to 63-4 illustrate different parameters and apparatus fortesting tear resistance according to an embodiment of the invention; and

FIG. 64 illustrates apparatus for testing total mask flow according toan embodiment of the invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The following description is provided in relation to several embodimentswhich may share common characteristics and features. It is to beunderstood that one or more features of any one embodiment may becombinable with one or more features of the other embodiments. Inaddition, any single feature or combination of features in any of theembodiments may constitute additional embodiments.

In this specification, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting only of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “comprised” and “comprises” where they appear.

The term “air” will be taken to include breathable gases, for exampleair with supplemental oxygen.

The term “seal” will be taken to mean to reduce the flow of air betweenthe pressurized interior of the mask and the ambient conditions to alevel sufficient to maintain a therapeutic pressure in the airways toeffect treatment. Hence in some cases, there may be an air tight seal,in other cases there may be a small leak.

1. Introduction

A mask assembly used to facilitate the delivery of a supply of air orbreathable gas to the entrance of the airways of a patient typicallyincludes a generally soft, conforming interfacing structure, at least aportion of which is in contact with the patient's face and a stabilizingstructure that positions and retains the interfacing structure in asuitable position with respect to the patient. The mask assemblytypically includes some form of anchor point to which various componentsmay be connected, or about which they may be arranged. In thisspecification, this anchor point will be referred to as the frame.

By way of example, the stabilizing structure of the mask assembly may becalled “headgear” and both the headgear and interfacing structure may beconnected to a frame. In some forms of mask, the boundary lines betweenthe different components may be blurred. For example, aspects of frameand headgear may be combined.

The interfacing structure may perform two or more functions: (i) acushioning function, performed by a cushioning component, and (ii) aninterconnection function, performed by a cushion-to-frame component orclip portion. Generally, in this specification the term “clip” or “clipportion” may describe the aforementioned clip portion or a cushion toframe component for securing the cushioning component to a frame of amask.

Forming the interfacing structure from two separate elements enableseach to have different properties, such as different densities or airpermeabilities as suits their different roles, as will be described inmore detail in the following sections. Furthermore, the differentproperties of different materials can act to influence the othercomponent. For example, a more rigid clip or cushion-to-frame portioncan act as a support structure for a softer cushioning component.

However, in another embodiment, the interfacing structure may beconstructed from a single component with different properties indifferent regions of the interfacing structure. Furthermore, theinterfacing structure may be formed from more than two components.

The interfacing structure may be constructed and arranged to apply airor breathable gas to both the nose and mouth (a “nose & mouth” or“full-face” mask), or to the just the nose (a “nose” or “nasal” mask),or just the mouth (a “mouth” mask).

The statement “more rigid” may be understood to mean less flexibleand/or stiffer.

2. Cushion Component 2.1 Material

In one form, the cushioning component may be made from an unskinned, lowdensity, permeable foam. In a preferred embodiment, the cushioncomponent is constructed from a low resilience viscoelastic polyurethanefoam. The cushioning component material may be manufactured from a freerising slabstock foam process. In other embodiments the material may bemanufactured by other processes such as molding or other known processesused to produce soft and cellular materials. One or more fabricationsteps (known as conversion techniques) may then be applied to thematerial to partially or completely form the geometry of the cushioncomponent. These conversion techniques are described herein and in otherrelated specifications referenced herein. Such a foam material andconversion techniques are disclosed in PCT Publication Nos. WO2008/011682, published Jan. 31, 2008, and WO 2008/070929, published Jun.19, 2008, each of which is incorporated herein by reference in itsentirety. In one form, the cushioning component may be formed in wholeor in part by a known method such as die cutting. Die cutting isdisclosed in PCT Application PCT/AU2009/000262, filed Mar. 4, 2009. Inanother form the cushioning component may be formed in whole or in partby using other methods such as those disclosed in AU 2008904769 and AU2008904778.

Most foam material production techniques produce a material that has asubstantially skinned material such that the density of the material atthe surface is greater than the density of the material's bulk(internal) properties. The utilization of particular manufacturingtechniques, such as foam conversion processes involving cutting, mayallow the production of a unskinned cushioning component such that thebulk properties of the cellular material are exposed at the surface ofthe cushioning component, providing a number of advantages to thedesign, manufacture and performance of the mask assembly.

The unskinned cushion component provides improved sealing, comfort andfit range performance, sealing properties sufficient to not require asilicone membrane, and a unskinned mask assembly that allows utilizationof the bulk properties of the unskinned material, e.g., porosity forbreathability, fine cell structure for a comfortable feel.

2.2 Shape

The interfacing structure is preferably constructed and arranged to havea three dimensional shape defined in part by a locus of pointssurrounding and complementary to the entrance to the relevant airways.Furthermore, the interfacing structure has a cross-section chosen atdifferent points around its perimeter to provide efficacy and comfort bybeing suitably shaped to adapt and conform to the face of the userforming a compression-type seal. In another configuration, a flap-typeseal is formed.

The shape of the interfacing structure may be adapted to allow thecushioning component to provide a better fit and seal against the faceof the patient.

In an embodiment, the geometry of the cushion may be at least partlydetermined by the geometry of the frame to which it is to be attached.For example, the general shape of a small size cushion may be differentthan the general shape of a large size cushion because the small andlarge size frames may be different, e.g., the small may be more stout orwide while the large may be more elongated and thinner.

2.2.1 Full Face Mask

FIGS. 16 g to 16 i show various cross-sections through one embodiment ofthe cushioning component 932 (origin of cross section shown in FIG. 16f), FIG. 19 shows an alternative embodiment of the present inventionwith corresponding cross sections in FIGS. 20-25.

FIGS. 33-38 depict a further preferred embodiment of a interfacingstructure wherein the interfacing structure includes a co-molded orotherwise attached cushioning component and a clip portion

Preferably, the full face masks depicted in this specification may havecushioning components about 105-110 mm in width (as measured from theouter most edges of the base surfaces); and a length of between 120-150mm.

Nasal Bridge Region

As shown in FIG. 16 g, the cross section at the nasal bridge region NBis generally triangular. The cross section at the nasal bridge region NBmay also be another other reasonable shape, such as generallyrectangular, oval, octagonal etc. In addition, it is possible for thecross section at the nasal bridge region to include a shape withgenerally rounded or curved corners. The cross section at the nasalbridge region may also be an irregular shape. FIG. 20 shows analternative cross section for the nasal bridge region.

There is a radius r1 at the apex 2010 of the cross section, that may berelatively small or sharp radius at the nasal bridge region NB. Forexample, radius r1 may be between 1 to 4 mm. This relatively small orsharp radius at radius r1 provides the advantage that the cushioningcomponent is kept away from the patient's eyes, especially when thecushioning component is compressed and inflated with air pressure inuse. The relatively small or sharp radius at radius r1 may also enableminimal contact of the mask with the patient's skin, so as to make themask feel more comfortable and less obtrusive.

As best shown in FIG. 20, apex 2010 of the generally triangular crosssection may be skewed or offset. The apexes or the corners of thegenerally triangular cross sectional may be rounded to promote a betterfit with the patient and/or a better seal. This offset is shown on FIG.20, where apex 2010 and center line 2015 are spaced by distance 2020.Distance 2020 may be preferably around 1-2 mm at the position proximalto the patient's nose. The comparable offset in the cushioning componentabout the portion adapted to cover the bottom lip of the patient ispreferably 8 mm. The comparable offset in the cushioning component aboutthe portion adapted to cover the cheeks of the patient is preferably1.25 mm. FIG. 20 demonstrates an offset towards the inner edge of thecushioning component. Alternatively the apex may be skewed, or over theouter edge of the cushioning component.

Additionally, the generally triangular cross section of the cushioningportion may also additionally be defined has having three sides: aninner side which faces into the centre of the mask; an outer side facingaway from the centre of the mask and a base surface, which may beadapted to be joined to a clip portion, at least in part.

The outer side of surface of the cushioning portion is generally adaptedto be longer than the inner surface. This may allow the cushioningcomponent to, in effect, roll, bend or move inwards. The rolling motionleads to an extension of the sealing surface formed between the skin ofthe patient and the cushioning component. As the cushioning component isdepressed, the contact region against the patient's skin is lengthenedfrom the minimum contact point which is the apex to at least partiallyextending along the outer surface or side of the cushioning component.

For example, the apex of the triangle that contacts the user's face(FIG. 58) enables the cushion component 932 to deflect or roll such thatif the apex is towards the inner part of the cushion component, thecushion component will roll inwards and over the clip portion 934 abouthinge point 939. Air pressure AP from the CPAP device (FIG. 59) acts onthe back of the rolled section of the cushion component 932 such thatthe air pressure forces the cushion component into sealing engagement onthe patient's face.

The rolling effect or the turning moment force, when the mask is pressedonto the face, can be also increased or assisted the positioning orshape of the clip portion attached to the cushioning portion.Preferably, the clip portion 3234 may be joined to the base surface ofthe cross section of the cushioning component. More preferably, the clipis mounted proximal to the outer side of the cushioning component, andprovides little or no support relative to the inner side of thecushioning component. Preferably, the clip portion may not generallysupport the inner side of the cushioning component.

Preferably, the clip portion includes a stepped configuration whenviewed in accordance with its cross section. In FIGS. 27-32, a preferredclip portion is joined to a cushioning portion. The steppedconfiguration is adapted to mate with a corresponding groove, slot orrecess in the frame to provide aa seal. In this embodiment, the stepformation is oriented towards the outer side of the cushioning componentfor ease of use by the patient.

Preferably, the clip portion is joined to the cushioning component by anupper side. The upper side of the clip portion may be shaped to assistwith: sealing of the cushioning component; comfort; and/or theaforementioned rolling effect of the cushioning component. In FIGS.30-31, the upper side of the clip portion has been angled towards thecentre of the mask by lengthening the outer side of the clip portionrelative to the shorter inner side of the clip portion. This angling ofthe upper surface of the clip portion is adapted to aid or assist in therolling in effect of the cushioning component. Additionally, in theembodiments shown in FIGS. 26-32, the angled upper side of the clipportion has been included on the lower corners of the mask. For example,as shown in FIGS. 30 and 31, the upper surface of the clip portion isangled to enhance rolling and sealing in lower cheek and lip regions(e.g., a1 and a2 between about 0-20°). As shown in FIG. 32, the angle ofthe upper surface in the chin region (e.g., a3 between about 0-20°) isoriented opposite that in the lower cheek and lip regions (e,g., thebottom lip region) (FIGS. 30 and 31), e.g., for manufacturability.

Preferably, the upper corner which is adapted to engage the nasal bridgeof the patient, the upper surface of the clip portion is flat and notangled towards to the centre of the mask. This is generally because theregion around the nose doesn't require as much “roll” as the sealingarea against the sides of the nose is relatively long compared theregions around or about the cheeks of the patient. This feature isdemonstrated in FIGS. 27 and 28.

Preferably, the nasal bridge region also includes a modification to thebase surface, wherein the base surface has been reduced or shortened tothereby reduce the volume of foam material rolled inwards at the nasalbridge.

FIG. 32 depicts the interfacing structure wherein the upper surface ofthe clip surface has been angled outwards relative to the centre of themask. This reduces the effect of “roll in” in the predetermined regionsincluding this outwardly disposed angle of the upper surface. Generally,the outwardly disposed angle of the upper surface is suitable forregions requiring reduced “roll in” such as around the bottom lip oraround the upper lip (in the nasal mask configurations). Another way toregulate “roll in” is by changing the amount of overhang of thecushioning component with respect to the clip portion.

As shown in FIG. 16 f, the inner apex 2050 of the cushion has the radiusof curvature of between 3 to 10 mm (most preferably 3-5 mm). This issimilarly shown in FIG. 19, where the inner apex 2050 of the cushion hasthe radius of curvature. The size of this radius may affect thedurability, and more specifically the tear strength of this region.

As shown on FIGS. 16 g and 20, inner edge 2090 may have an angle 2100from the base of the cushioning component. Angle 2100 may influence theamount of the cushioning component that may contact the patient. Forexample, angle 2100 shown in FIG. 16 f may be larger than angle 2100shown in FIG. 20, such that more of the cushioning component in FIG. 16f may contact the patient's face than that of FIG. 20. Preferably, angle2100 may be about 90-95 degrees. The angle of the outer side or edgemeeting the base surface is preferably between 78-83. Preferably, theangle by which the outer side meets with the base surface is generallyless than the angle formed between the inner side and the base surface.

The most preferred maximum width of the nose bridge region (as measuredalong the base surface) is 22 mm and most preferred maximum height ofthe cushioning component at the nose bridge position is approximately 24mm.

Bottom Lip Region

As shown in FIG. 16 g, the cross section at the bottom lip region BL maypreferably be generally trapezoidal. The cross section at the bottom lipregion BL may also be another other reasonable shape, such as generallyrectangular, oval, octagonal etc. In addition, it is possible for thecross section at the bottom lip region to include a shape with generallyrounded or curved corners. The cross section at the bottom lip regionmay also be an irregular shape. FIG. 25 demonstrates this feature in across section for the bottom lip region.

Preferably, in the embodiment depicted in FIG. 25, the apex 950 isskewed towards the centre of the mask, the outer side or surface of thecushioning component at the region that is adapted to contact the bottomlip region of the patient. The outer side has been divided into an upperand a lower portion, wherein the upper portion is at a reduced angle inrespect to the lower portion. The apex 950 is adapted to rest or engagethe cleft formed between the bottom lip of the patient and lowerextremity of the chin. The upper portion is adapted to engage thepatient's face at a position lower and extending away from the cleft.Thereby providing an increased sealing surface between: the patient'sface at the location between the bottom lip and the lower extremity ofthe chin; and the outer side of the cushioning component.

As best shown in FIGS. 16 g and 25, the patient contacting surface 940is generally flat or has a larger radius r2 when compared to the nasalbridge region radius r1. This arrangement aids in comfort and increasesthe length of the sealing surface such that a better seal may bemaintained.

In FIG. 25, the radius r2 at the apex of the cushion is preferably about5 mm.

Alternatively, patient contacting surface 940 may have apex 950 that mayfirst contacts the patients face and anchors the cushion in the dimpleof the chin or curvature between the lower lip and chin region. Apex 950may have a relatively small radius r2 when compared to that radius r2shown in FIG. 16 g. Radius r2 may be about 5 mm. Patient contactingsurface 940 may also have a kink or inflexion 960 that may generallymatch the approximate curvature of the chin so as to rest the cushion onthe chin to sealingly engage the cushion with the patient. This kink 960also allows apex 950 to flex inwards towards the centre of the cushion,and outwards away from the centre of the cushion, so as to accommodatemovement of the patient's chin or jaw. For example, it is possible forpatients to drop their jaw during sleep, so in order to maintain a sealwith the patient, the mask must be able to move with the patient's jaw.This arrangement further enables a greater fit range of patients, i.e.kink 960 may flex either inwards or outwards on a patient's jawdepending on the length and depth of their chin, other facial featuresetc.

Additionally, as shown in FIGS. 16 g and 25, the internal wall 942 ofthe cushioning component is arranged substantially vertical or normal tothe face of the patient in use as demonstrated by angle 2150. Thisarrangement reduces the likelihood of the foam cushioning componenttouching the patient's bottom lip when compressed in use, a problem thatmay occur for larger faces within each size range.

The preferred maximum width of the cushioning component as measured inrespect of the base surface is generally about 35 mm in relation to thebottom lip region. The preferred maximum height of the cushioningcomponent is generally about 26 mm in relation to the bottom lip region.

In FIG. 25, the angle formed between the outer side and base surface isapproximately between 80-90 degrees; and the angle formed between theinner side and the base surface is approximately between 90 to 100degrees. Preferably, the angle by which the outer side meets with thebase surface is generally less than the angle formed between the innerside and the base surface.

Side of Nose Region

As shown in FIG. 16 h, the cross section at the side nose SN isgenerally triangular. The cross section at the side nose region SN mayalso be another other reasonable shape, such as generally rectangular,oval, octagonal etc. In addition, it is possible for the cross sectionat the side nose region to include a shape with generally rounded orcurved corners. The cross section at the side nose region may also be anirregular shape. FIGS. 21 and 22 show an alternative cross section forthe side of nose region.

FIG. 16 h shows a cross-section of the cushioning component in a side ofnose region SN. Similar to the nasal bridge region NB as shown in FIG.16 g, the cross section is generally triangular. However the triangularcross section is skewed or biased towards the inner edge of thecushioning component. This arrangement aids with sealing because innerwall 944 abuts the side of the patient's nose in use, thereby increasingthe sealing surface. This is similarly demonstrated in FIGS. 21 and 22.

Preferably, the outer side is longer than the inner side. Alsopreferably, the angle formed between the outer side and the base surfaceis generally less than the angle formed between the inner side and thebase surface.

The most preferred maximum width of the side of nose region (as measuredalong the base surface) is 22 mm and most preferred maximum height ofthe cushioning component at the side of nose position is approximately24 mm.

Cheek Region

As shown in FIG. 16 i, the cross section at the cheeks C is generallytrapezoidal or triangular. The cross section at the cheeks region C mayalso be another other reasonable shape, such as generally rectangular,oval, octagonal etc. In addition, it is possible for the cross sectionat the cheeks region to include a shape with generally rounded or curvedcorners. The cross section at the cheeks region may also be an irregularshape. FIGS. 23 and 24 show an alternative cross section for the cheekregion.

FIG. 16 i shows a cross-section of the cushioning component in a cheekregion C. As illustrated, the contacting surface or apex 946 where thecushioning component contacts the patient's cheek is similar to that atthe bottom lip region BL as shown in FIG. 16 g. The cross section isgenerally triangular, and may have a smaller top surface 946 whencompared to the top surface 940 of the bottom lip region BL. Thisarrangement aids sealing around the patient's cheeks in use andincreases the comfort of the interfacing portion, while reducing thebulk of the interfacing portion at the cheek region C.

A similar arrangement is shown in FIGS. 23 and 24. However, as shown inFIG. 24, inflexion 950 changes the curvature of the side wall of thecushion so that it may hinge or bend inwards. This may increase theability for the cushion to seal on the patient's face when in use.

Preferably, the outer side of cushioning component is longer than theinner side. Also preferably, the angle formed between the outer side andthe base surface is generally less than the angle formed between theinner side and the base surface.

The most preferred maximum width of the cheek region (as measured alongthe base surface) is 23 mm and most preferred maximum height of thecushioning component at the cheek region is approximately 24 mm.

Additionally, when the clip portion is joined or mounted to thecushioning component, the apex of the cushion is additionally offsettowards the centre or middle of the mask. In the described embodiments,the apex may be offset to the extent that it overhangs the point formedbetween the inner side and the base surface.

2.2.2 Nasal Mask

FIGS. 39 to 47 show an alternative embodiment of the present invention.Cushion component 4000 may be used as a nasal mask that only covers thenose of the patient in use, and is positioned on the nose bridge, sideof nose, cheeks and or upper lip region and may not cover the patient'smouth.

Preferably, the cushioning component of the nasal mask shown in respectof these embodiments is preferably: 70-75 mm in length (when measuredfrom the outer most edges of the base surface of the cushioningcomponent); and the width of the cushioning component is approximately75-80 mm.

Nasal Bridge Region, Side of Nose Region and Cheek Region

The nasal bridge region 4200, side of nose region 4300 and cheek region4400 may be generally similar to that described above for a full facecushion.

The preferred height of the cushioning component at the regiondesignated to correspond to the nasal bridge of the patient isapproximately 22 mm. The height of the cushioning component at theposition designated to meet the side of the nose is approximately 25-27mm. The height of the cushioning component at the position designated tomeet the patient's cheek regions is approximately 27 mm.

The preferred width of the cushioning component in the side of noseregions is typically about 20 mm. Whereas the preferred width of thecushioning component in the cheek regions is typically about 18 mm.

Upper Lip Region

As shown in FIGS. 39 and 41, cushion component 4000 may have an upperlip region 4100 that has a dip or region of reduced height (when viewedfrom a side view as shown in FIG. 41) relative to the height of otherregions 4200. This feature may accommodate various upper lip regions ofpatients whilst avoiding accidental occlusion of the nares. The overallreduction in the amount of foam material may reduce the risks forpatients.

The preferred width of the cushioning component in the upper lip regionis typically about 16 mm. The width of the cushioning component in theupper lip region may be 10-20 mm. The width of the cushioning componentin the upper lip region may be 15-20 mm. The width of the cushioningcomponent in the upper lip region may be 12-20 mm. The width of thecushioning component in the upper lip region may be 10-15 mm. The widthof the cushioning component in the upper lip region may be 10-18 mm. Thewidth of the cushioning component in the upper lip region may be 10-14mm.

The preferred height of the cushioning component at the regiondesignated to correspond to the upper lip of the patient isapproximately 18 mm. The height of the cushioning component in the upperlip region may be 10-20 mm. The height of the cushioning component inthe upper lip region may be 10-25 mm. The height of the cushioningcomponent in the upper lip region may be 15-20 mm. The height of thecushioning component in the upper lip region may be 16-23 mm.

Fit Range

Because of the wide range of sizes and shapes of different people'sfaces, it is a continual challenge for mask designers to determine theleast number of mask shapes required to fit the broadest range ofpatients. In one ideal form, a single mask shape would fit all patients.

A mask assembly in accordance with the invention provides an improvedfit range. This maybe preferably achieved by combining a morecomfortable and compliant material with a more anatomically neutralgeometry that seals against a wider range of facial anatomy for a givenshape.

The versatility of a chosen cushion shape, and hence its fit rangeperformance, is also enhanced by the ‘hovercraft’ behavior exhibited bythe cushion. In this context the “hovercraft’ behavior is generallydefined by the air pressure in the cavity of the mask when the airpressure in cavity of the mask is greater than the outside environmentalair pressure and thereby allows the mask to float on the face of thewearer. The pressure seal is preferably formed by the cushioningcomponent. This feature may enhance the ease and speed of fitting themask.

When pressurized with air the cushion material has extra extensibilitycompared to other known cushion materials. The soft flexible cells inthe foam material effectively stretch when inflated allowing thematerial the freedom to enlarge. This allows the cushion material tohave an extra dimension of conformability over other cushion materialsknown in the art e.g. silicone, by being able to expand and morph tofacial anatomy when inflated with air pressure. This is, in part, alsoachieved by combining an expandable open-cellular structure in directcommunication with the air that is providing the positive airwaypressurization. It is the flow of air through the sealing material thatforms a fine layer of pressurized air between the facial skin, and theflexible nature of the cushion material that enables this hovercrafteffect, hence making it easier to fit to the face. The foam being lesssticky than silicone also has a significant advantage in achieving aneasy, fast and comfortable fit.

2.3 Method of Manufacturing

The following manufacturing techniques may be used to create a range ofshapes and cross-sections as may be required for different facialshapes. Since the cushioning component is preferably made from unskinnedfoam, one or more cutting processes may be used to create the part, suchcutting processes including die cutting, and/or machining, etc.Alternatively the cushioning component may be molded with measures takenin the process to minimize the skin on the foam component, or the skinbeing subsequently removed from the molded component in a post processe.g. machined. Preferably, the foam material used in the hereindescribed embodiments may be an open and closed cell foam. The foammaterial used may be an open cell foam. The foam material used may be aclosed cell foam.

2.3.1 Die Cutting

In the illustrated embodiment shown in FIGS. 4 a-4 g, both an insidesurface and an outside surface of the foam cushion component 232 are diecut. This typically results in generally straight cut edges. The cushionin these embodiments may have a generally rectangular cross section,where the top surface is generally substantially parallel to thepatient's face in use, and the inner and outer side surfaces aregenerally perpendicular to the patient's face in use. It may be possibleto die cut the foam using additional processing steps to create anon-rectangular cross section, e.g. the use of shims. The die cutting ofa cushion component then from a flat sheet of foam results in a flatbacked cushion component which may subsequently take the shape of a clipthat it is assembled to e.g. glued. The foam cushion is thereforedeformed into its final intended shape.

To create a curved backed cushion, that for example matches the shape ofa curved clip without stretching or deformation, the cushion componentmay be die cut from a foam sheet that is cut into a curved shape ratherthan a flat sheet. The curved sheets may be formed from a known processreferred to as contour cutting, where a foam block is cut into curvedsheets by being fed into an oscillating blade that changes position andorientation during the cutting process.

In addition to die cutting or in the alternative, the cushioningcomponent, e.g., as shown in FIGS. 9 a to 12 f, may be cut into athree-dimensional shape or geometry using the techniques described in AU2008904769 and AU 2008904778.

FIGS. 9 a to 9 d illustrate a foam-based interfacing structure 430including a foam cushion component 432 and a clip portion 434. Outerwall 400 may include contours and curvature incorporated into thedesign. The inner, patient contacting wall (or orifice) 402 may be diecut as known in the art. Again, this typically results in straight cutedges (e.g., see FIGS. 9 b and 9 d).

FIGS. 10 a to 10 c illustrate a foam-based interfacing structure 330including a foam cushion component 332 and a clip portion 334, whereinthe cushion component 332 includes localized regions with curvature orridges, e.g., ridges 350 along cheek regions of the cushion component, acurvature 352 along the nasal bridge region of the cushion component,etc. In addition, the cushion component 332 is contoured along the chinregion of the cushion component. The straight die cut inner and outeredges remain perpendicular to the patient's face in use similar to theprevious embodiment.

FIGS. 11 a to 11 c illustrate a foam-based interfacing structure 530where a localized region 552 in the cushion component 532 at the nasalbridge has been raised, e.g., formed with a curved surface.

FIGS. 12 a to 12 f illustrate another embodiment in which a foam-basedinterfacing structure 630 including a foam cushion component 632 and aclip portion 634, wherein the foam cushion component 632 includes a slabof foam that is cut using methods known in the art. This process may berepeated in order to cut the outer wall 600 of the cushion component andthen the inner, patient contacting wall (or orifice) 602 of the cushioncomponent.

3. Clip Component 3.1 Material

The cushion-to-frame component may be made from a material that hasgreater structural integrity than the cushioning component. In apreferred embodiment the clip is made from polyurethane foam that hashigher hardness, higher density, and lower permeability than the foamused for the cushioning component. The clip/cushion-to-frame componentmay be formed in a mould giving rise to a harder, denser, lowerpermeability foam having a skin. In an alternatively preferredembodiment, the clip may be constructed of a non-foamed polymer, forexample (but not limited to), nylon, polycarbonate, polypropylene.

Preferably, the clip portion or clip component may be of reducedhardness or increased flexibility in comparison to the frame portion ofthe mask to which it is to connected or secured with.

3.2 Shape

The clip 934 is shown generally in FIG. 13, and in more detail in FIGS.15 a-15 e. The clip 934 is generally shaped in order to align with theframe. However, the general curvature of the clip 934 can be altered tosuit the frame to which it is to be fitted. The general curvature of theclip may also be used to shape the cushion component. Since the cushioncomponent is made from compliant foam, it will readily adapt to theshape of the clip when joined together. An example of where this may bean advantage is when the cushion component is made to have a flat back(from a flat foam sheet as described previously) and is given its finalshape by assembly (e.g. glued) to a clip that gives the cushion itsintended shape (e.g. curved).

The clip may also be made flat. The cushion can therefore also be madewith a flat back to match the clip. The overall intended shape of theinterfacing structure (combination of clip and cushion) can therefore bealternatively achieved by the flat clip and cushion being deformed andretained into a curved frame. This embodiment allows clip to bemanufactured flat which can have several advantages including ease ofhandling and alignment during manufacture, packaging and transportation.The clip can therefore be formed by alternative methods e.g. die cuttingfrom flat sheet material.

The clip may also be made curved. This may be achieved by several meansincluding molding directly into a curved shape, die cutting from curved(contour cut) sheet, or heat forming a flat clip die cut from athermoformable material. Having the clip curved allows ease of alignmentand assembly to a curved frame, as well as giving the cushion a curvedshape if the cushion is made from a process that results in it having aflat back.

In a preferred embodiment the clip is made from molded polyurethane. Thecushion contacting surface 935 is generally smooth so that it cancontinuously join and seal to the underside of the cushion. Cushioncontacting surface 935 has a lip 935 a to enable alignment of the clipto the frame.

Frame contacting surface 937 has three alignment tabs 938 protrudingfrom its surface that engage with the frame. There may be any number ofalignment tabs 938 to aid the patient in aligning the interfacestructure with the anchoring structure. It should also be appreciatedthat the clip need not have alignment tabs 938 to engage the clip withthe frame.

The clip may also be made to incorporate features that engage the frameto aid retention of the interfacing structure to the frame. Examplesinclude, but are not limited to, surface roughening, ribs, notches,snaps etc.

3.3 Method of Manufacturing

The clip component may be separately formed as will be now described, orinsert molded as will be described later in this specification.

By way of example, FIGS. 18 a to 18 c illustrate a tool to mold a clipportion by itself, where the clip portion may subsequently be attachedto the cushion component, e.g., by an adhesive or simply adhesionbetween the clip and cushion component. As illustrated, the toolincludes a top half 1560 and a bottom half 1565 which are adapted to bejoined together to form the clip portion. As shown in FIG. 18 b, thetool provides a curved parting line PL between the top and bottom halves1560, 1565.

The bottom half 1565 includes a cavity 1567 adapted to receive thematerial (e.g., foaming mixture) that will form the clip portion. Also,the center section 1568 of the bottom half 1565 accommodates a separateinsert that acts as a manual ejection feature after molding. The tophalf 1560 provides a surface 1562 that will form the side of the clipportion for interfacing or joining with the cushion component.

The top and bottom halves 1560, 1565 of the tool are constructed and/orarranged to facilitate demolding of the clip portion from the tool sothat the clip portion will not adhere to the tool. For example, the topand bottom halves 1560, 1565 may be constructed of a material from whichthe mold material (e.g., foaming mixture) may be removed (e.g., highdensity polypropylene, silicone). Alternatively, a demolding agent(e.g., wax) may be provided to the top and bottom halves to facilitatedemolding.

An alternative demolding aid may be a release film that lines the tooland releases from the clip material easily after molding. In a preferredembodiment the release film may double, in whole or in part, as thepackaging for the interfacing structure such that the product leaves themolding process already packaged. In another embodiment the clipincludes a tab at one or a number of locations that facilitates grippingof the part for demolding during the manufacturing process. This tabfeature may also double as an alignment feature for assembly and agripping feature for disassembly for the user of the mask assembly.

In another embodiment the clip may include a tab feature that includesan end of life indicator for the interfacing structure.

4. Sub-Assembly 4.1 Relative Position

In accordance with an embodiment of the invention, a range of differentarrangements of clip portions and cushion components may be provided.For example, the width of the clip portion may preferably match or beless than the maximum width of the cushion component, the width of thecross section of clip portion may be less than the width of the crosssection of the cushion component. In these different configurations withdifferent relative widths, the clip portion provides different forms ofsupport to the cushion component.

Wherein the width of the cross section of the clip portion is less thanthe width of the cross section of cushion component, the clip portionand cushion component may be arranged such that (i) the outer perimeterof the clip portion and cushion component align (hides hardness of clipportion and provides desired freedom of movement in the cushioncomponent), (ii) the inner perimeter of the clip portion and the cushioncomponent align, or (iii) neither the inner or outer perimeter of theclip portion and the cushion component align.

Similarly, wherein the width of the clip portion is greater than thewidth of the cushion component, the clip portion and cushion componentmay be arranged such that (i) the outer perimeter of the clip portionand cushion component align, (ii) the inner perimeter of the clipportion and cushion component align, or (iii) neither the inner or outerperimeter of the clip portion and the cushion component align.

When the width of the clip portion is less than the width of the cushioncomponent and the outer perimeter of the clip portion aligns with thecushion component, the cushion component may preferably be more able toflex in regions or directions not having a clip portion next to it thanin regions having a clip portion adjacent to it or supporting it. Forexample, where the cushion component overhangs the clip portion, thatoverhanging region of the cushion component has more freedom to move.This arrangement can be more comfortable and more able to adapt todifferent geometries of a person, and provide the correct vectors toseal the cushion component against the face.

Preferably, the clip portion is to be joined to a cushioning componentby a base surface of the cushioning component. It may also be preferablyto arrange the clip portion to support the external extremity (relativeto the circumference of the mask) of the base surface and to have no orlittle support inner extremity of the base surface.

When used as part of a respiratory mask, it may be preferable that theinner portion of the cushion component overhang the clip portion. Inthis arrangement in use, the face of the patient may engage with anunsupported inner edge of the softer cushion component causing it tobend and conform to the individual patient's shape. When the maskengages a patient's face, the cushioning component may roll inwardstowards the centre of the mask when pressure is applied on the masktowards the patient's face.

FIG. 7 a shows an elevation view detail from the frame side of theinterfacing structure 230 shown in FIG. 4 e in a nasal bridge region. Asshown in cross-section in FIG. 7 b, it is apparent that the width w2 ofthe clip portion 234 is less than the width w1 of the cushion component232 and that the outer perimeter of the clip portion 234 and the cushioncomponent 232 are aligned. An advantage of this arrangement isillustrated in FIG. 7 c where in use the nose is able to push the innerperimeter of the cushion component 232 in the direction shown by thearrow, in a cantilever manner as well as compressing. FIG. 8 is across-section showing the clip portion 234 of the interfacing structure230 received within the channel 22 of a mask frame 20.

This arrangement is in contrast to prior art cushions (such as theLifecare™ mask shown in FIGS. 6 a and 6 b) where the inner perimeter ofthe cushion C abuts the frame F, and hence it is not free to moveinwardly and can only compress.

FIGS. 26-32 show an alternative embodiment of the present invention.FIG. 26 shows the cross sections later shown in FIGS. 27-32. Cushioncomponent 3232 may be attached to clip component 3234. Cushion component3232 may be similar to that shown in FIGS. 19-25. Clip component 3234may have upper surface 3500 that attaches to cushion component 3232.Upper surface 3500 may be generally horizontal when in use or assembled,as shown in FIGS. 27, 28, and 29. In addition, this may position thetangent to apex 3600 of the cushion component 3232 generally parallel toupper surface 3500. Alternatively, upper surface 3500 may be generallycurved or angled inwards towards the inner portion of the cushion so asto angle the cushion more towards the centre of the patient's face, asshown in FIGS. 30, 31, and 32. Therefore, tangent to apex 3600 may notbe parallel to upper surface 3500. In an embodiment, the upper surface3500 may be angled in one or more selected regions, e.g., lower cheek orchin regions to fit patients with more narrow, shallow faces (see FIGS.30-32).

In an embodiment, as shown in FIGS. 27-32, the outer edge of the cushioncomponent may slightly overhang (e.g., 1 mm overhang) the clipcomponent, e.g., for manufacturability.

4.2 Glue

The two layers (i.e., the cushion component and the clip portion) may beadhered to one another using polyurethane hot melt glue orcyanoacrylate.

In alternate embodiments (not shown in Figures) the cushioning portionmay be directly glued onto the frame.

4.3 Insert Molding

In a manufacturing process according to an embodiment of the presentinvention, insert molding may be used to assemble the cushioningcomponent to the cushion-to-frame component. An advantage of thisapproach include lower cost when compared to other processes such asgluing.

FIGS. 17 a to 17 h illustrate a tool and manufacturing process formanufacturing an interfacing structure according to an embodiment of thepresent invention.

As best shown in FIG. 17 a, the tool includes a first portion 1060adapted to receive the cushioning component that may be cut from foamslabstock and a second portion 1065 adapted to receive the foamingmixture that will form the cushion-to-frame component.

The first portion 1060 of the tool may allow a vacuum to be applied tothe cushioning component to retain it in position. For example, as shownin FIG. 17 a, the walls of the cavity that receive the cushioningcomponent include a plurality of orifices 1062, and a vacuum is appliedto an opening 1063 in the side wall of the first portion 1060 so thatthe cushioning component may be drawn into the cavity. The first portion1060 may be sized to provide an interference fit with the cushioningcomponent.

The first and second portions 1060, 1065 of the tool are arranged sothat there will be a region of contact between the cushioning componentand the cushion-to-frame component such that they will adhere to oneanother.

At least a second portion of the tool is constructed and/or arranged tofacilitate demolding of the cushion-to-frame component that wouldotherwise adhere to the tool. Preferably, this is achieved by using atool constructed of a material from which the foam may be removed (e.g.,high density polypropylene, silicone). Alternatively, steel or aluminumtools may be used, provided an appropriate de-molding agent can be used,such as wax (e.g., agent that does not present biocompatibility issues).

In the illustrated embodiment as best shown in FIG. 17 a, the secondportion 1065 includes three parts that are removably attached to oneanother, i.e., an inner portion 1066(1), and outer portion 1066(2), anda ring portion 1066(3).

An insert molding manufacturing process according to an embodiment ofthe invention will now be described in greater detail.

FIG. 17 a illustrates the first and second portions 1060, 1065 of thetool separated from one another. In FIGS. 17 b and 17 c, the cushioningcomponent 1032 is placed in the first portion 1060 of the tool. Thecushioning component 1032 may be held in place in the first portion 1060by a vacuum and may impart curvature on the cushioning component via thevacuum. This may be necessary if the cushion is made from a process thatgives is a flat backed geometry. Placement of the cushioning component1032 may be manual or automated. For example, the cushioning component1032 may be sucked into the first portion 1060 using the vacuum.

In FIG. 17 d, a mixture of polyurethane (e.g, foam or elastomer) isprepared to form the cushion-to-frame component 1034 and thehigh-intensity mix is poured into the second portion 1065 of the tool.Pouring of the mix for the cushion-to-frame component 1034 may be manualor automated. If the cushion-to-frame component 1034 is made from a foamthe cavity of the second portion 1065 will only be partly filled (e.g.,25%) and during the foaming process it will expand to fill the space andcome into contact with the cushioning component where it will adhere.

In FIG. 17 e, the first and second portions 1060, 1065 of the tool areclamped together or closed to allow the cushion-to-frame componentfoaming reaction to proceed in the tool. That is, the foam for thecushion-to-frame component 1034 can rise up and chemically bond oradhere to the foam cushioning component 1032. The choice of clipmaterial may enhance the bonding or adhesion process. In a preferredembodiment both the clip and the cushion are made from polyurethanematerial for ideal bond integrity between the two components.Additionally, should the cushion component have a regular, uniform,rough, irregular or non-uniform cell structure, the clip component mayinfuse into gaps in the cell structure of the cushion component, formingsmall mechanical bonds between the components.

When the cushion-to-frame component 1034 has cured, the vacuum firstportion and second portion are separated as shown in FIG. 17 f. In FIG.17 g, the ring portion 1066(3) at the bottom of the second portion 1065is removed and the inner portion 1066(1) is ejected to demold thecushion-to-frame component 1034. FIG. 17 h shows the resultinginterfacing structure 1030 removed from the tool with the cushioningcomponent 1032 adhered to the cushion-to-frame component 1034. In apreferred embodiment the cushion component is originally flat whenvacuum inserted into the top half of the tool and is bonded to a curvedclip during the insert molding process. The resultant interfacingstructure then assumes an intended curved shape.

In an alternative embodiment the cushion and clip are made flat but thecushion is made with sufficient depth to not require curvature tosuitably adapt to the face when worn; but rather suitably deforms to theshape of the face due to the softness and depth of the cushion foam.

In another alternative arrangement, a film may be added to the secondportion of the tool prior to the addition of the foaming mixture. Thisfilm may be structured to facilitate removal of the otherwise adheringcushion-to-frame component. The film may be used to form packaging forthe interfacing structure.

In an embodiment, the clip portion of the interfacing structure may beconstructed from more rigid and denser foam than the cushion component.For example, the clip portion may be formed from nitrogen blownpolyethylene, or some other biocompatible foam having a finecell-structure. Alternatively, the clip portion could be made from someother polymer or rubber. In an embodiment, the clip portion is adaptedto form a cushion-to-frame engagement mechanism and to form a structuralsupport for the cushion component.

Preferably, the cushioning component is less rigid, less stiff or moreflexible than the clip portion, which is in turn less rigid, less stiffor more flexible than the frame of the mask. Preferably, the frame givesshape to the mask interfacing structure, wherein the interfacingstructure is relatively flexible and less rigid, overall than the frame.This feature adds comfort and also allows the interfacing structure tobe easily replaced by the patient or user. Further improvements to theinterfacing structure may be made to adapt the shape and configurationto be disposable.

For example, FIG. 13 shows a clip portion 734 including a side 735 forinterfacing with a foam-based cushion component and a side 737 forinterfacing with a mask frame. In this embodiment, the clip portion 734is constructed of a skinned foam and may be formed by molding. The foamof the clip portion 734 may be harder or more dense than the foam of thecushion component. Alternatively, the more dense or harder foam may beformed by cutting, e.g., die cutting, machining, and/or the methods setforth in AU 2008904769 and AU 2008904778.

This arrangement provides a one piece interfacing structure with acushion component adapted to engage the patient's face and a clipportion adapted to interface with the mask frame.

In one form, a mask system may be provided that includes at least twodifferent forms of interfacing structure chosen from the set offoam-based cushion, silicone-based cushion, and gel-based cushion.

FIGS. 14 a to 16 i illustrate an interfacing structure 930 including acushion component 932 and a cushion-to-frame component or clip portion934 provided to the cushioning component 932. FIGS. 14 a to 14 f showthe cushioning component 932 attached to the cushion-to-frame component934, FIGS. 15 a to 15 e are isolated views of the cushion-to-framecomponent 934, and FIGS. 16 a to 16 i are isolated views of thecushioning component 932.

As shown in FIGS. 14 a to 15 e, the cushion-to-frame component 934includes a side 935 for interfacing with the cushioning component 932and a side 937 for interfacing with a mask frame. The side 937 includesprotrusions 938 to facilitate and/or enhance attachment to the maskframe.

5. Assembling the Frame and Interfacing Structure

The interfacing structure is constructed as described above and arrangedfor removable interconnection with the rest of the apparatus, forexample a respiratory mask.

The ability to removably connect the interfacing structure enables oneto replace the interfacing structure should it become soiled, damaged,uncomfortable or otherwise aged as a result of usage. It alsofacilitates trial or testing of different arrays of interfacingstructures which are selected an different patients facial types orfeatures (e.g., narrower face, longer nose, ox longer chin, etc.). Oneform of interfacing structure, for example a foam-based interfacingstructure, may be used as a form of “training” system to allow a personto become accustomed to the sensation of wearing and using a mask. Afoam-cushion based mask may provide an initially more appealing andcomfortable surface for a new patient than a gel or silicone-basedcushion. The patient may subsequently switch from the foam-based cushionto a silicone or gel based cushion. In this way, the patient may be morelikely to adhere to therapy because they are used to the very softcomfortable feeling of foam.

When applied to respiratory equipment, the interfacing structure isadapted for connection with a mask frame. In use, a seal is formedbetween the interfacing structure and the frame. This arrangement couldbe used for both nasal and full-face masks. The seal between the frameand interfacing structure may seal better wherein the clip portion isless rigid or more flexible than the frame.

For example, FIG. 1 illustrates a mask 10 including a mask frame 20 afoam-based interfacing structure 30 provided to the mask frame 20. Asillustrated, the foam-based interfacing structure 30 provides a foamcushion component 32 adapted to contact the patient's face in use. Inthis embodiment, the foam-based interfacing structure 30 is adapted foruse with an existing mask (e.g., ResMed's Mirage Quattro mask), whichallows the patient to switch from the foam-based interfacing structure30 to the mask's existing silicone-based cushion if desired.

FIGS. 4 a to 4 g show a foam-based interfacing structure 230 accordingto an embodiment of the invention. As illustrated, the interfacingstructure 230 includes a cushion component or face-contacting portion232 and a clip portion 234 provided to the cushion component 232. Inthis embodiment, the clip portion 234 is adapted for an interference fitwith a mask frame, and the width of the clip portion 234 is narrowerthan the width of the cushion component 232 (e.g., see FIGS. 4 e and 4g).

5.1 Cushion-to-Frame Engagement Mechanisms

According to an aspect of the invention, the cushion-to-frame engagementand connection mechanism provided by the clip portion may include achannel-type engagement or rib-type engagement.

As shown in FIG. 2, the channel-type engagement includes a foam clipportion 34 that is adapted to be received within the channel 22 of amask frame 20 with an interference fit. The foam clip portion 34 extendsaround the entire perimeter of the interfacing structure so as to form aseal and retention with the mask frame.

As shown in FIGS. 3 a to 3 c, the rib-type engagement includes a foamclip portion 34 with one or more slots 38 to receive inner and/or outerribs 23, 24 of the mask frame 20. For example, the slot to ribengagement may provide an inner frame rib engagement (see FIG. 3 a), anouter frame rib engagement (see FIG. 3 b), or an inner and outer framerib engagement (see FIG. 3 c). This arrangement provides a broader baseof support for the sealing foam.

FIGS. 5 a and 5 b illustrate a foam-based interfacing structure 830including a foam cushion component 832 and a clip portion 834, and FIG.5 c illustrates the interfacing structure 830 provided to a mask frame20. As shown in FIGS. 5 a and 5 b, the clip portion 834 includes a slot838 adapted to receive a rib of the mask frame 20. Also, providing awider clip portion 834 allows more stiffness and structural integrity tobe provided to the clip portion, making the clip portion easier toassemble to the mask frame.

When structured to form an interference fit with the mask frame, theclip portion may have the following properties: appropriate rigidity(e.g., less than that of the frame and in one form more rigid than thefoam cushion component); non-porous; and/or low compression set (theamount of deformation expressed as a percentage of original dimensions)which a material retains after compressive stress is released (in thisway, the clip portion maintains its retention force during its usagelife).

Additionally, the clip portion may include an additional extension (notshown) that extends beyond the outer extremity of the frame which isadapted to be gripped by the patient for easier removal of theinterfacing structure. Preferably, this extension would be positioned ina region that is easy for the patient to grip such as the nasal bridgeof the mask. Preferably, the extension will be small enough not toimpede vision of the user or to affect the overall efficiency or seal ofthe mask. Preferable, the extension may function as a finger grip forthe patient to remove or replace the interfacing structure, whendesired.

FIGS. 50-1 to 57-2 illustrate alternative mechanisms for attaching theclip portion to the frame. In FIGS. 50-1 and 50-1, the clip portion 5034is in the form of a microcellular polyurethane clip adapted to engagewithin the frame channel 5022 with an interference fit. In FIGS. 51-1and 51-2, the clip portion 5034 is in the form of a flexible plasticclip (e.g., Hytrel, TPE) adapted to engage the frame channel 5022 with asnap fit. The clip portion also includes a lip seal 5035 adapted toengage the channel wall. In FIGS. 52-2 and 52-2, the clip portion 5034is in the form of a flexible plastic clip adapted to engage the framechannel 5022 with a snap fit. The clip portion also includes a sealingelement 5035 (thermoplastic elastomer that may be over molded on to theclip portion) adapted to engage the channel wall. In FIGS. 53-1 and53-2, the clip portion 5034 is in the form of a polyurethane clipadapted to engage within the frame channel 5022 with an interferencefit. The clip portion also includes a flexible plastic clip 5036(assembled to the polyurethane clip) adapted to engage the frame channelwith a snap fit. In FIGS. 54-1 and 54-2, the clip portion 5034 is in theform of a polyurethane clip adapted to engage within the frame channel5022 with an interference fit. The clip portion also includes a flexibleplastic clip 5036 (glued to the polyurethane clip) adapted to engage theframe channel with a snap fit. In FIGS. 55-1 and 55-2, the clip portion5034 includes a flexible plastic clip adapted to engage the framechannel 5022 with a snap fit or other fitting means e.g, interferencefit. In addition, the clip is contoured such that the clip also engagesthe channel wall with an interference fit. In FIGS. 56-1 and 56-2, theclip portion 5034 includes a flexible plastic clip adapted to engage theframe channel with a snap fit. The clip portion also includes a foamelement 5037 adapted to cover the clip. In FIGS. 57-1 and 57-2, the clipportion 5034 includes a polyurethane clip (attached to cushion componentby plastic element 5038) adapted to engage the frame channel 5022 with asnap fit. The frame channel includes a plastic extension 5023 adapted toengage the clip. This arrangement allows replacement of the cushioncomponent without the need to change the clip portion.

6. Exemplary Materials and Properties

The following provides exemplary materials and properties of the cushioncomponent and clip portion.

6.1 Cushion Component

In an embodiment, the cushion component may be made from polyurethane,be resistance to hydrolysis and/or resistant to microbial attack.

In an embodiment, the cushion component may be air permeable. In anembodiment, the cushion component may not be air permeable.

In an embodiment, the cushion component may be able to maintain its airpermeability over a period of use.

Preferably, the cushion component may not emit harmful or odorousvolatiles or particulates.

Preferably, the cushion component may be coloured and this colour maynot fade.

FIG. 48 is a chart showing exemplary material properties for the cushioncomponent.

In one example, properties of the foam cushion component may include:density (relates to other foam properties and affects cost and weight ofthe cushion, e.g., higher density can reduce air permeability and higherdensity can increase hardness); air permeability (flow of air throughcushion contributes to total mask flow characteristic of the mask whichmay affect compatibility with PAP devices); hardness (affects comfortand sealing performance); tear resistance (contributes to durability);tensile strength (contributes to durability); and/or tensile stiffness(resists the deforming effects of positive air pressure inside themask).

6.2 Clip Portion

FIG. 49 is a chart showing exemplary material properties for the clipportion.

In one example, properties of the foam clip portion may include: density(affects weight); air permeability (permeability of the foam itself maynot be critical if it is molded with a skin that renders itimpermeable); hardness (soft and flexible enough to assemble to theframe with an interference fit and seal against the frame);elasticity/viscoelasticity (soft and flexible enough to assemble to theframe with an interference fit and seal against the frame); and/orcompression set (should not deform over time to ensure easyassembly/retention).

6.3 Testing Methods

The following provides exemplary testing methods for determiningmaterial properties.

6.3.1 Air Permeability

Air permeability is defined as “the rate of air flowing through a foamsample (in L/min)”.

This test measures the flow through a regular shape with a constantcross section, in a manner analogous to a cushion in real use. In theexample of FIG. 60-1, the test specimen is an annulus of foam, about 30mm thick. The circular shape ensures that pressure is evenly distributedand the foam inflates uniformly.

The foam sample is cut normal to cell rise direction as shown in FIG.60-4.

The wall section of the foam specimen may be rectangular (see FIG.60-2), but it is possible for the wall section to have a concave outersurface and a convex inner surface (see FIG. 60-3).

The annular foam sample is held at a defined height between two platesin a Universal Test Machine (e.g., Instron). Air at a given pressure isdirected into the centre of the annulus and flows out through the foam.The air flow rate and reaction force of the foam against the plates maybe measured. FIG. 60-5 is a schematic of the test set up.

As shown in FIGS. 60-6, 60-7, and 60-8, the test jig used to hold thefoam consists of: an aluminum base plate that locates the foam and sealsagainst the flat bottom surface of foam annulus; an air inlet andpressure port in the centre of the base plate; a clear polycarbonate topplate that seals against the flat bottom surface of foam annulus andallows observation of the test sample; and a part glued to the top plateto connect with a load cell attachment on the Universal Testing Machine(UTM).

Once set up, attach the top plate to the crosshead of the UTM, zero theload cell of the UTM.

Zero the displacement of the UTM at the uncompressed height of the foamsample, i.e., 30 mm above the base plate sealing surface.

If there is variation of 1 mm or more in the thickness of the samples,then for each sample: (i) assemble the foam sample into the test jig;(ii) lower the crosshead just until a positive force is read on the UTM,e,g., 0.2 N; and (iii) zero the displacement.

Lower the crosshead at 50±20 mm/min until 40% compression displacementis reached.

Immediately record the reaction force, at 0 cmH₂O.

Wait 60 seconds and again record the force.

Immediately but gradually adjust the flow generator to 4 cmH₂O (andimmediately record force and flow rate.

Wait 60 seconds and again record the force and flow rate.

Repeat steps 7 and 8 for 12 cmH₂O and 20 cmH₂O.

6.3.2 Hardness

Hardness is defines as “force required to indent a test piece of foam toa stated percentage of its original thickness”.

Hardness may be tested using an IDM Universal Test Machine, orequivalent (e.g., see circular flat indenter of FIG. 61)

If applicable, precondition the foam as specified in AS 2282.2-1999.

Test the foam according to AS 2282.8-1999 Method A—Indentation force ondeflection test.

Report IF₄₀, the reaction force at 40% compression after 60 secondsindentation, H60s.

Also report the reaction force at 40% compression after 2 secondsindentation, H2s.

Report the sag factor or support factor, i.e., the ratio of 65% to 25%IFD value.

6.13 Tensile Strength

Tensile strength may be measured using an IDM Universal Test Machine, orequivalent. See FIG. 62-1.

Test both directions, i.e., parallel to and normal to the direction ofcell rise.

Apply the following deviations from AS 2282.6-1999:

Do not reject test pieces that break outside the gauge length.

Record whether the test piece did break, did not break or came out ofthe jaws before maximum elongation was reached.

Three test pieces may be acceptable if the results are consistent (noindividual value deviates more than 20% from the mean of the threevalues).

Select a typical or representative results curve by inspecting thegraphs. Select a suitably linear region near the start of the curve.(The start of the curve is more representative of real use than anextremely stretched region and also ensures the result is not affectedby the test sample sliding out of the gripping jaws.)

Calculate the change in force over a distance of at least 25 min anddivide by the distance to obtain the stiffness value in N/mm.

For example, the curve in FIG. 62-2 is most linear near the start of thecurve, between 25 mm and 50 mm. Stiffness was calculated as follows.

k _(tensile) =ΔF/Δx=(F _(50 mm) −F _(25 min))/(50−25)

6.3.4 Tear Resistance

Tear resistance is defined as the force required to propagate a tear ina pre-cut sample. See FIG. 63-1.

Test according to AS 2282.7-1999 with the following parameters:

The speed of separation of the jaws holding the test piece shall be 200mm/min.

Test all three directions defined in FIGS. 63-2, 63-3, and 63-4. Testand report the tear resistance results (σ_(t)) for each directionseparately.

Apply the following deviations from AS 2282.7-1999;

Do not use a knife or blade to assist the direction of tear. Allow thefoam to tear naturally.

It may not be possible to tear a 50 mm length of foam. Tear as far aspossible up to 50 mm.

Total Mask Flow

This test measures the flow through only the foam cushion, by blockingthe mask vent all other leak paths. See FIG. 64.

The cushion is compressed by 40% of its 30 mm thickness, i.e., 12 mm.

7. Other Features

In an embodiment, a mask frame may be integrally molded or formed withthe cushion-to-frame component 1034. For example, the second portion1065 of the tool may be structured to mold the cushion-to-framecomponent together with the mask frame.

In the illustrated embodiment, a polyurethane foam cushioning componentis provided to a polyurethane foam or polyurethane elastomercushion-to-frame component. In an alternative embodiment, one or both ofthe components may be constructed of a gel material. For example, bothcomponents may be constructed of gel, the cushioning component may beconstricted of gel and the cushion-to-frame component may be constructedof foam, or the cushioning component may be constructed of foam and thecushion-to-frame component may be constructed of gel.

While the invention has been described in connection with what arepresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention. For example the cutting techniques used for thecushioning component may also be used for the clip component, or theinterfacing structure. Also, the various embodiments described above maybe implemented in conjunction with other embodiments, e.g., aspects ofone embodiment may be combined with aspects of another embodiment torealize yet other embodiments. Further, each independent feature orcomponent of any given assembly may constitute an additional embodiment.In addition, while the invention has particular application to patientswho suffer from OSA, it is to be appreciated that patients who sufferfrom other illnesses (e.g., congestive heart failure, diabetes, morbidobesity, stroke, bariatric surgery, etc.) can derive benefit from theabove teachings. Moreover, the above teachings have applicability withpatients and non-patients alike in non-medical applications.

1.-4. (canceled)
 5. A facial mask for use in providing a supply of airat pressure to the entrance of the airways of a person comprising a foamcushion that forms a face contacting portion to effect a seal, across-section of the cushion tapers from a wider cross-section to anarrower cross-section closer to the face and the tapered portiondefines an inside surface adjacent an interior of the cushion and anoutside surface.
 6. The facial mask of claim 5 wherein the insidesurface and the outside surface are adjacent.
 7. The facial mask ofclaim 6 wherein the inside and outside surfaces are arranged at an acuteangle.
 8. The facial mask of claim 5 wherein in cross-section theoutside surface is longer than the inside surface in a first region ofthe cushion.
 9. The facial mask of claim 8 wherein the first region is anasal bridge region.
 10. The facial mask of claim 8 wherein incross-section the outside surface is approximately the same length asthe inside surface in a second region of the cushion.
 11. The facialmask of claim 10 wherein the second region is a chin region or a lipregion of the cushion.
 12. The facial mask of claim 5 wherein in atleast one region of the face, a seal is formed on at least part of theoutside surface.
 13. The facial mask of claim 5 wherein in a vegionadjacent the side of the nose the cushion has a triangularcross-section.
 14. A cushioning component for use with a mask, whereinat least a portion of the cross section of the cushioning componentincludes: inner side defined by the side facing the centre of the mask,an outer side defined by a side facing away from the centre of the mask;and a base side facing the frame or clip portion; wherein the length ofouter side is greater than the inner side.
 15. A interfacing structurefor a mask, comprising a clip portion joined to a cushioning component,wherein an upper surface of the clip portion is joined to a base surfaceof the cushioning component; and wherein at least a portion of the uppersurface is angled to provide a moment force on cushioning component,when force is applied into the cushioning component.
 16. The interfacingstructure of claim 14, wherein the upper surface is angled towards thecentre of the mask and the moment force is directed into the centre ofthe mask.
 17. The interfacing structure of claim 14, wherein the uppersurface is angled away from the centre of the mask.
 18. A interfacingstructure for a mask, comprising a clip portion joined to a cushioningcomponent, wherein an upper surface of the clip portion is joined to abase surface of the cushioning component; and wherein the crosssectional width of the clip portion is less than the cross sectionalwidth of the cushioning component,
 19. The interfacing structure ofclaim 18, wherein the clip portion is disposed proximal to the outerside of cushioning component.
 20. The interfacing structure of claim 19,wherein the positioning of the clip portion relative to cushioningcomponent promotes a moment force, when force is applied to thecushioning component.
 21. A cushioning component for use with a mask,wherein at least a portion of the cross section of the cushioningcomponent includes: inner side defined by the side facing the centre ofthe mask, an outer side defined by a side facing away from the centre ofthe mask; and a base side facing the frame or clip portion; wherein theouter side further comprises at least an upper and a lower portion,wherein the upper portion at a reduced angle in comparison to the lowerportion.
 22. A nasal mask comprising: a frame removably connected to aninterfacing structure, wherein the interfacing structure includes acushioning component constructed of foam material, and wherein theheight of the interfacing structure is reduced in relation to regionthat is adapted to contact the upper lip region of a patient's face. 23.A foam cushion for use with, a mask, the cushion including an outer sidewall and an inner side wall, wherein at least a portion of the inner andouter side walls taper together and wherein at least a region of theouter side wall contacts the patient's face, when in use.
 24. Thecushion of claim 23 wherein at least one said portion is located on thesides of the nasal bridge or on the nasal bridge.
 25. The cushion ofclaim 24 wherein the inner and outer side walls are adjacent.
 26. Thecushion of claim 25 wherein the inner and outer side walls tapertogether at an acute angle. 27.-53. (canceled)